IPv6

128-bit address (=~10³⁸ addresses) =32 hex digits in 8 blocks of 4 (8 hextets of quartets).

Abbreviation: Drop leading 0's in block. One consecutive run of blocks of 0's to a ::.
2601:04C3:4002:BE00:0000:0000:0000:0066 to 2601:4C3:4002:BE00::66

48-bit Global Routing Prefix given by IANA/RIR/ISP. First 3 blocks / 12 digits.
80-bits: 16-bit subnet, 64-bit hosts.

Typically, both network and host IDs are 64-bits:
2001:0DB8:8B00:0001:0000:0000:0000:0001/64 in subnet 1
2001:0DB8:8B00:0002:0000:0000:0000:0001/64 in subnet 2

IP6 Ranges:
2000-3FFF global unicast. 2000::/3    1/8 of all. Publicly routable.
2001:db8 Examples only.
FE80-FE8F link-local unicast. FE80::/10    Not routable (cf. IP4 APIPA). Can be used as next-hop addresses for static routes. NDP uses them.
FD00-FDFF unique local unicast. FD00::/7    Routable in LAN (cf. IP4 private). Originally started FC.
FF00-FFFF multicast. FF00::/8    Addresses for groups. FF02::1 is essentially a broadcast.
85% of IP6 addresses are reserved.

Loopback address: ::1

EUI-64 = MAC OUI with bit 7 flipped + FFFE + MAC serial
Can be used as the "host portion" of a /64 IPv6 address, see below.
8c:2d:aa:4b:98:a7 → 8E2D:AAFF:FE4B:98A7
18:b4:30:10:7b:61 → 1AB4:30FF:FE10:7B61

Static assignment of IPv6 address based on MAC address:
64-bit GPR/subnet + EUI-64

No broadcasts; uses multicast instead. NDP (network discovery protocol) w/ ICMPv6 instead of ARP.

6to4: 4in6, Teredo mixed networks.

DNS: AAAA record